Wilma Ragland here, awake in the dark. Today is the big day: a few hours after breakfast we're entering orbit around Njord. Should I be doing this? Tiger tells me, you're it, you're going to be the only person from Earth to describe the only planet in reasonably accessible space with life on it. I'm no planetographer; I'm a recycled petroleum geologist, and not a brilliant one at that. I started out worrying about that, and Tiger and Willie talked me out of it, sort of, but now it's not a game any more: I'm going to have to perform. I'd better talk to Tiger, privately, before the menfolk wake up.
Very carefully I slip out of my sleep web and get my head end inverted toward the center of the ship, as Willie quietly snores centimeters from my body. Even in the dim lighting we use at night, it's easy to distinguish Tiger's midnight black foot pads from Simba's lion colored ones. I poke a horny sole and snatch my hand back. Tiger was nice enough to show us where to touch to get her or Simba awake without an instinctive defense slash, but I know what those claws can do. Tiger's foot and tail jerk in her web; then she imitates me by carefully inverting without bumping Simba. We'll talk by Tiger signs, her one-handed language that she developed to cope while recovering from her terrible accident.
Tiger: You're excited to finally find out what's happening on this planet? I sure am.
Me: Well, that's what I wanted to talk to you about. You know I'm just a petroleum geologist. I don't have a research degree.
Tiger: You'll do fine! You're aggressive; you asked those profs the right questions at Georgia Tech. And you don't have to do the research alone. All of us want to get our noses in, and you'll have everyone's resources to draw on. But you studied geology professionally, while we're just amateurs; you know what amphibolite is, for example. You have what it takes, and we'll help.
Me: But I'm... not supposed to be here. You know.
Tiger: No, I don't know. I say who's supposed to be here, and it's you.
Me: Can I tell you something? I've never told anyone this before, not even Willie. In my undergrad psych class the prof told us, it had something to do with psychodynamic theory or some such, how some little black kids try to wash the black off. Everyone was saying how dumb the kids were, or how the racial background made them ignorant, or some Marxist crap about oppression, and I smiled and giggled along with the rest, but it was a lie. My mom's best washcloth and a lot of squirts of her best soap... I didn't tell her; you're the only person I ever told.
Tiger: Well, um, um, we aren't exactly talking about amphibolite here. Um. Look, I think you deserve something in exchange from me. Did you ever wonder why I'm the strongest of the original lions? When we were training on our mat you commented on the exercises I do that Simba doesn't; only my Emerald does them because he makes it a contest with his supervisor. I'm a scaredy cat. Since I was really, really little I felt I had to keep strong to survive an attack from an unnamed adversary. I haven't kept it a secret like you did, but it's not the Tiger persona people usually see. You're hurt; are you asking me for help how to deal with the hurt?
Me: You're scared inside? You?
Tiger: Of course I'm scared inside! Who wouldn't be, where we are? You mean about my kitten scaredy. As soon as Ms. Holbeck realized what I was trying to tell her she taught me that I'd do the same things whether I was scared or not, right? My mind is recognizing some kind of danger and when I feel afraid I should be extra careful. The unnamed adversary is a real threat for lions, or humans too, popping up out of nowhere, and it's good to be strong, as long as I don't let the fear overbalance my life and stop me from enjoying what I'm doing. The fear is there; it's a part of me that shouldn't be ripped out; but I don't let it hold me back.
Me: So you're saying I... Well...
Tiger: I assume you're asking for advice. We've been friends for a long time and we've talked about being a lion, but never about being a specifically black human. The topic never seemed useful; I guess Simba and I are used to Willie's attitude and we never caught on that you were different inside. You are black, or what we'd call auburn, and unlike me you can't change your skin or fur color. If you tried to wash it off then you apparently don't like being black, and that's not going to change either. And I'm going to glue together bits of several lessons which I'm sure you'll recognize: whether or not you like your skin, the geology you do today will be the same, right? You don't do geology with your skin, do you? And your choices are to do the geology with joy, plus the other baggage you can't change, or to let your bad feelings slop over into your geology, not have the joy, and probably mess up the job too. Does that make sense?
Me: It's hard. Deep inside me it's telling me that I'm no good.
Tiger: Not to agree, but I can understand where that feeling might come from; I've read enough about race, and public schools. Can you tell that part of you to shut up, as I think you've been doing for a long time?
Me: I'll do my best. On the geology, I mean.
Tiger: That's what I expect of you, no more and no less. I let my scaredy cat say what it wants me to do, or not do, and then I do what I want to do. Can you listen to that unconfident voice, then walk away from it?
Me: I will. I won't just try, I'll succeed. I have to live with what I am.
Tiger: And what you are is very good; be sure of that! Now I think it's time to wake up the males. OK?
Tiger jabs Willie's and Simba's feet, quite a bit more forcefully than I poked hers. And she also snatches her hand back from Simba, but not from Willie, who can, and does, only kick.
Tiger: Wake up, you lazy lunks! We have a big day coming up, and we have already started planning what we're going to do.
Actually Tiger is just psyching the menfolk for my benefit. She's a good friend, a really good friend. And I'm going to do what she said: I'll do my best, and it will have to do, and I'm going to put on the biggest display of nerve in my life and put my observations and conclusions in front of all of Earth, and I'll do it with joy, and I will succeed, and I won't snivel in my pillow whining to be what I can't be.
We're still far out, moving fast, but we're decelerating. Our trajectory is preprogrammed to drop us over the planet's pole, missing the worst of the van Allen belt radiation, on the likely assumption that Njord has van Allen belts. As we cross the pole Tiger will delicately reorient the ship and the pods and bags trailing behind, and put us into a low circular orbit inclined about 45 degrees, missing the aurora zone and mostly protected from stellar hard radiation by the van Allen trap. Tiger will supervise that maneuver, though letting the computer do the detail work, but we have two hours to exercise with the new barbell simulator, to clean up and to eat. Not that it takes long to eat two ration bars. From our angle of approach the planet is a crescent and we see mostly the night side, so I can't even take panoramic views. A lot of space flight is just waiting.
But now we're in orbit, 175 kilometers above the surface. Njord is a bit smaller than Earth, and the density is less, probably because this system has less metals than Sol, but the main difference in appearance is that it looks like desert all over. It's a lion colored planet.
I have the telescope programmed to track the ground so the camera can take unblurred pictures, and I've preplanned a grid of nearly nonoverlapping frames. Whenever we're over a frame that hasn't been seen or that's been done at a poor sun angle, we'll save the image, or otherwise just the difference from the previously saved image, and on this first orbit we're seeing a new frame every seven seconds or so. We're collecting eight channel multispectral data, two thousand pixels square, or fifty kilometers square on the ground. We'll be storing, and sending to Earth, about a quarter million images over the coming month. As soon as the last pusher chip and its partner are manufactured and installed we'll set the orbiter loose in a polar orbit and it will capture images complementary to what our camera gets, particularly of the polar regions that we can't see.
With Simba's help I've also written a recording program for the low resolution external views, and a viewer based on NetBoard so on our consoles we can point features out to each other, look at any stored image, or see the low and high resolution frames at the same time.
I also have the infrared spectrometer set up to automatically watch the star at each sunrise and sunset; well, what are we supposed to call them, starset? Epsilon-set? The altitude dependence of the strange absorption bands may give a clue what they are.
We're all glued to the console screens. I can't handle a frame every seven seconds; I grab the latest frame and go over it until I've seen what's there, what a cursory and non-expert look will reveal, taking a minute or sometimes two, and then I go on to whatever we've moved over in that time. Maybe Simba can see things faster, or maybe he doesn't know as much geology and has fewer things to see, but he seems to be looking at the frames in real time. Tiger and Willie, I'm not going to take time out from watching the planet, to find out their pattern.
Simba: What in hell is that? It looks like a slime dump!
Tiger: Look at low res, people. It's a kind of crescent, all in icky green.
I switch to that image, and superimpose what high resolution frames we got, in a diagonal stripe across it. In the future the whole square will be filled, but the recorded data is pretty clear: the yellow-green expanse is in a depression. I punch in our radar altimeter data; we were going over a gently rolling plain, but it suddenly rose into low hills and then dropped three hundred meters to a nearly geometrically flat surface.
Me: That's its ocean, people! I'm sure that's water.
And the radar altimeter shows a more gradual rise of about two hundred meters, and the lion colored terrain resumes.
Me: Possibly we're looking at like the Tonga trench except with the ocean drained. We should be watching for mid-ocean ridges and back-arc spreading centers. And look what the altimeter... Wow, check out the magma in the last frame; we hit a live one! You can see stuff on this planet that you could never see on Earth.
Simba: That's cool, I mean, hot! Which is that, mid-ocean or back-arc?
Me: I don't know; I'll have to see the pattern when we get more high-res frames.
Simba: Check this one out; doesn't it look like a volcano?
Me: A nearly dead one, with the top shredded by erosion, like Maui on Earth. See on the low-res: there's a string of them: Hawaii on Njord. But it's funny: with the erosion there, where did the water go? The deep canyons just fade out on the volcano's flanks.
Tiger: Tag all these frames in your note files. Later today we're going to have to break off and write up our impressions, and plan what to dig for information on. But not now! Enjoy the view. Except I have an interruption: I have to change chips in the prototyper and start the partner chip for the orbiter. This will just take a few minutes. Put notes on my page of things I'm missing, please.
Me: And judging from the sun angle we're about to go to the night side, and I want to see the sunset spectrum. There, light is gone. You didn't miss anything, Tiger.
By evening we've had five full orbits. The schedule of half day, half night gave us time to decompress after each one, and to eat our ration bars for lunch. But by now we're saturated, and it's a bit of a relief to let the computer handle storing the images and to concentrate on flattening our six hundred grams of frozen Chang non-sprouts in the rolling mill, stewing them into mush, and enjoying our two-course meal with another ration bar each. We also have a tomato which the four of us share, and shredded bits of two kinds of peppers, the first we've had: while we were still at the comet Simba planted some of the vegetables and they're just starting to bear fruit. We had a few Chang sprouts die on us, but it looks like the rest are going to be healthy, so our bellies will be happy for as long as we want to extend the mission. That's a big emotional load off us.
After dinner we get to work writing up our observations, figuring out what we were seeing, and planning what to look for tomorrow. We have several first impressions of Njord. First, Njord has fully developed plate tectonics despite the shortage of water. Multiple continental highlands have formed, similar to present-day Earth, and among them runs a clearly visible and active mid-ocean ridge system. What would be ocean bottom on Earth, we're calling it ``plate surface'' here. We've seen several deep subduction trenches on the plate surface, and likely there are more we haven't seen.
But only the two biggest trenches seen so far are filled with water. I got infrared reflectance spectra of both, and they're packed with chlorophyll (and by inference, with living plants): probably the source of the oxygen in the atmosphere, that was detected all the way back at Earth. The rest of the planet within the latitude band that we fly over is various kinds of bare dirt. The higher the land is, the more the dirt is eroded by water, but we saw not a single cloud.
The mysterious atmospheric absorption bands extend up to about thirty kilometers and then fade out. There is no analog in natural atmospheric processes on Earth for those bands; nothing in our infrared spectrum database. We'll have to build our lander, send it down with a gas bottle, and get a sample to find out what the stuff is. Probably the stink of alien plants being rotted by alien bacteria. The ultraviolet signature of ozone is only about five percent what Earth has. That is explained partly by the lower ultraviolet production of epsilon Eridani, cooler than Sol, but even so there should be more ozone -- in the range of 20 to 35 kilometers.
There's a minor mystery: occasionally the altimeter signal drops out, as if the radar waves just aren't being reflected. That data is important, and it wouldn't be nice if the altimeter were broken. Simba has already started to work on the problem, and he's found that when the altitude of the terrain before and after the dropout is plotted it's invariably highland but not the highest places. Of course, and fortunately, we don't have too many samples so this conclusion is tentative. Simba has a diagnostic program patched in, and with luck in the morning we'll have more information, including actual waveforms.
The day started for me with unhappy emotions, and despite Tiger's psych speech I'm still not sure of myself interpreting all these strange features, but my friends seem to treat my observations with respect, and even anticipation, and this evening I'm feeling much more that it's all going to work out, both the geology and the food. The peppers really helped, making me feel a whole lot less precarious. It's time now for sleep and peaceful dreams. Willie is sweet, but not in the scent department, particularly given the difficulty we have keeping clean with our limited water recycling capability. I'm sure I'm no better. But I really enjoy cinnamon and allspice to dream by.
Indeed, in the morning Simba finds the cause of the altimeter problem: the signal jitters erratically by twenty to thirty meters. The altimeter software decides that the instrument has gone wacko and throws out the data. By good luck, just before morning we travel southeast over one dropout area that we crossed to the northeast on our second orbit yesterday, and the signal drops out again, making us more confident that the fault is with the ground rather than the altimeter. Simba puts a filter into the software that averages out the jitters and tags the area ``jittery terrain'', rather than omitting the altitude reading entirely. We'll want to make jittery terrain one of the first spots we visit with the lander, if we could ever get the resources to build it.
On our third day around Njord the last partner chip is finished and Tiger installs it in the partner box for our orbiter, which we then launch. The data collection rate doubles and we get our first look at the polar regions. Since it's boreal summer the south polar zone is in permanent darkness, unfortunately, but the adjacent visible plate surface looks unremarkable and the altimeter shows no hidden islands or volcanos. In contrast, the two ``oceans'' extend to sixty degrees north, and on the opposite side of the planet near the arctic circle it looks like there was a recent flood basalt eruption.
We spend a month around Njord and by adjusting the orbiter's path we efficiently get a complete, high quality photomap and altimeter dataset. We're also reading the newsfeed at five times speedup; we're pretty religious about getting through five days of material each evening, splitting it between us. Most of it is going to be forgotten, by us and by the Terrans, by the time we get home, but there are a few items that bring a smile to our faces.
Willie: Look what I got: Wolf's graduation picture and an image of the commencement program. He graduated with honors, it says. I'm proud of our boy.
Me: Right on! Pass me the URL so I can see. Doesn't he look sweet in that silly hat?
Willie: And look at this letter. He and Wendy set the date, at last! From what he's written they're well matched.
Me: Right, they'll do well together. I hope they send all the wedding pictures. And pictures of the kids, so we can enjoy them from here.
We're now at the end of our work around Njord; we've done all we can without the lander. It's interesting to try to summarize what we're learning about this mysterious planet.
Me: Hey, people, could I get your help on a river valley here? I'm trying to write up an interpretation and it doesn't make sense. Look on the image at 110.8 east 52.3 north.
Willie: Got it. It looks like a valley. It drains into the eastern ``ocean'', right?
Me: Towards it, but I want to go upstream first. It's totally dry now, but look how broad the valley is, and the bed of the river. It was a wide, slow moving stream. Look to the right of center; see several little crescents there along the channel? Those are oxbow lakes, I'm sure. You see those on the Mississippi and all over the Amazon basin. I'm imagining what it was like: lush temperate forest, at least during summer, with lilies and sedges in those lakes, filling them in with plant debris. So where's the water now?
Willie: And how long has it been gone? I hope we can find out with the lander.
Me: Right. Now go 150 kilometers northwest into the mountains. That would be 109.2 east 53.1 north. In the upper right of that image, see the channel goes through a sandwich of hard, soft, hard rock. The river has a flat bed for five kilometers or so on the lower hard rock. OK, right in the middle a side canyon dumps debris into the channel all the way across: a typical alluvial fan. That's outrageous!
Simba: Why? It looks like a typical desert scene.
Me: The river stripped that channel easily once, but later you can't even see the river channel; it must have soaked into the fan and emerged as springs on the other side; see where there's some scalloped structure to the southeast. How could such a mighty river just vanish? Look at the big area it drains to the north. Rivers don't work that way. Now let's look at 112.6 east 51.8 north. In the northwest is the broad valley ending in a typical big delta deposit with multiple exit channels, except that the one on the right is enlarged into a deep canyon, and if you zoom it, I think the bed looks like hard rock. That goes for about forty kilometers, and the scar of the river is still there as it goes off the image, but switch to the next one: it just gradually fades out.
Tiger: This image reminds me of the Hudson and Scripps canyons. This isn't the first time we've seen that pattern.
Me: Right, we see that all over this planet: jumbled but otherwise normal water features above 60830 meters. A number of deltas right at 60830 and all have that incised main channel. Below that the only water features are the river channels. This one vanishes above 60000, and the longest one only makes it to 59800 meters altitude. The sea level must have been at 60830 for a long time, when the deltas were made. Then it dropped catastrophically. So where's the water now?
Willie: Hey, people, I think I know where it is. Yeah! The plasma instruments show a very high density of protons in the exosphere of this planet. Hydrogen isn't gravitationally bound. Solar ultraviolet dissociates stratospheric water vapor into oxygen and hydrogen, which gets blown away into space. And the planet is so lion colored. That's a sign of ferric iron. The leftover oxygen has rusted the crustal iron. It all fits!
Tiger: Good work, both of you! But...
Me: The infrared spectra show that the stratosphere is at 260 kelvin. Earth's is much colder, and only the tiniest amount of water can get up there. Njord's stratospheric cold trap stopped working: the mystery absorption bands! It has to be. Do you suppose some plant evolved and started putting out this stuff, that wrecked their atmosphere? We have to get the lander built, and take air samples.
Tiger: Definitely. Willie, how much have we mined?
Willie: 64 kilos, this morning. About one kilo per day. We should have enough metals for the second orbiter and the lander, and a little in reserve, if we're very sparing with copper wire like we were with this orbiter.
Tiger: Then tomorrow morning let's follow the schedule we planned: break orbit and head for Wotan and Thor. We'll fly the orbiter there separately and put it to work on Thor while we do the atmospheric observations of Wotan, and we'll have the miner meet us at Wotan with the raw materials. We won't be able to send the lander to Njord because with the speed of light delay, eight minutes the way the planets are now, we couldn't control it with any precision. But it should be ready to use on Thor, and on Loki, and we can get atmosphere samples on Wotan and Freyja.
Simba: I wish we could come right back here.
Tiger: So do I, but I really think we owe it to ourselves and the people on Earth to do a complete, disciplined job. And to survive to finish studying Njord afterward.
Me: I agree, Tiger.
Simba: To paraphrase Willie, I didn't say I was going to skimp on the other planets. But Njord is just such a puzzle!
Me: Yes it is, but I'm feeling pretty confident that we're understanding what the photomap is trying to tell us. I was worried at the beginning, but the geological processes we learned about do seem to apply to Njord. And I'll bet they're completely different on Thor. That one will be a real challenge, like Luna, our own neighbor which we've barely explored.
Tiger: So you worked through your worries.
Me: Like I told you, I have that little unconfident voice. But I don't do what it tells me, just like you, and it hasn't been so bad. Just jitters that one morning.
Tiger: I'm enjoying your analyses of Njord and I'm sure the geologists on Earth will be looking forward to them too, 10.8 years from now. People, I'm getting sleepy and I suggest we all get some rest, for tomorrow's work.
Me: I'd like to finish the writeup on the valley, and I'm sure Willie will want to at least make an outline of the report on exospheric water loss. It won't take long; we won't disturb you. Good night, Tiger.
The way Simba and Tiger are eyeing each other, I have a feeling Willie and I should do our work at the consoles at the far end of the ship. Or... Maybe the writeups actually could wait until morning.
In our four day passage to Wotan we write up our conclusions about Njord in a neat package. Yes, there are plenty of loose ends, but any interesting research project has those. And in the newsfeed there are several interesting items too.
Willie: Look at this URL. Lawsuits didn't stop the Chinese from putting up all those sundippers without paying royalties, and neither did conflicts with U.N. Orbit Control, and now we know what the power's going for. Not power to the people. Power to a starship. They announced the launch.
Tiger: Well, that's just great. They were so overbearing when we started the project, wanting to dictate who was going to be on the crew, and now we'll have to coordinate with them on activities here. I don't want to say this is my territory, but my animal instincts are enraged.
Simba: I see the article. What's this crap about serving the people? If I read between the lines, it seems to say emigration. Four people at a time? I wish there were more about the scientific payload on that ship. If any.
Me: Let's keep an eye out for details that may come later. This is just a press release worded to give the minimum information. Look at the next one; that one at least tells a story, and one I want to hear.
Tiger: That's a nice picture of Wolf and Wendy at the beach, but there's something just after it for me too. See my URL. Charlie got nominated for the SEC!
Simba: At last! Remember when we were all just out of college, what he said?
Tiger: As far as his skills can carry him, and he got what he wanted. A couple years earlier than I predicted, too. That's really cool.
Me: Yes, it is, but does he get confirmed? Let's read through this stuff quickly. Here's a report on the Armco collaboration; I'll look at it later and you'll want to also. Here's a transcript of hearings. Hmm, it's kind of long, but it looks like it didn't start out very well.
Simba: Maybe they let Moravech question him first to shut him up.
Willie: Listen to this crap: You're very, very different from citizens of the US of A, so how could you understand people's hopes and dreams for a comfortable retirement? Charlie goes, well, as a taxpaying citizen I have hopes and dreams too, and I hope and dream that you'll take a responsible line when the Social Security bill comes to the floor, so as not to disappoint so many retirees who are relying on your good judgment.
Tiger: Hah! Trust Charlie to stick the knife into that bag of wind. There, I've found the place. It doesn't seem to faze Moravech any, though. He tries to pin Charlie down on his position on Social Security. And Charlie demonstrates his skill wiggling out of the Senator's grasp. If I were on that committee I'd give Charlie a point for that, though I doubt they will.
Willie: See about two pages down. Moravech has been harping on how alien Charlie is, and Charlie comes back: Senator, you have that nice suit on; are you jealous because you'll never be as well dressed as I am in my own fur? I can open a letter with my claw; I don't need a brass unicorn letter opener like you have. (How did Charlie know that?) Do you seriously think that opal claws are the least bit important to securities policy? Come on, Senator, let's hear what's really on your mind. Now Charlie's trying to pin down Moravech and Moravech is wiggling away. The other senators should be splitting their sides with laughter.
Me: I doubt they are, though. Why doesn't the chairman muzzle Moravech?
Tiger: Here, I've been skimming, about halfway through Charlie ignores a Moravech jibe and asks, Mr. Chairman, the way the hearing has been going, we'll be talking all afternoon about whether it's appropriate for someone to hold a high government office who isn't a white male human. I'm willing to debate that as long as your bladder can hold out -- another difference between me and humans -- but I had prepared for a discussion of SEC policy and I imagine some of the other committee members will be disappointed not to get to that. Including some of the opposition members.
Me: The black Mr. Chairman, as I remember. Well, well! That seems to have jarred him out of somnolence. Now Senator Polk of Illinois is tearing into Charlie over stock index futures. What's the big deal?
Simba: Charlie thinks they destabilize the market and hasn't been shy about saying so, including to Senator Polk's face. The Chicago Board of Trade obviously wants them to continue and has let Senator Polk know what their campaign contributions are contingent on.
Tiger: What do I have to do, go back there and shoot my mouth off again to teach them to clean up the futures market? This is all arcane stuff that someone has a big financial interest in. Oh, there's some little detail where the questioner likes Charlie's answer. It's a real bladder-buster of a session, just like Charlie said, but the pro-Charlie people can't get the momentum going. The opponents are in the minority but are too vocal, so too many fence-sitters won't commit themselves. Doesn't look good. What's this, I thought she was on Charlie's side. She's suggesting that the chairman continue the hearing ``later''.
Me: That's bad?
Tiger: It means they're going to quit without a specific date to go at it again. The supporters are either going to twist arms until they have enough votes to move Charlie out of committee, or they're going to let the nomination go to mold. That would be a disappointment, for me and for Charlie.
Yes, it is a disappointment. By the time we get to Wotan it's clear to us, reading the newsfeed at five times speedup, that Charlie isn't going to get on the SEC. This time.
We've also sent the orbiter ahead of us since it has no need to coddle garden pods. It confirmed our expectation that the trapped radiation is fierce around Wotan and Thor, as it is around Jupiter, and now we get another turn to brave a radiation storm. Experts on Earth told us that the most valuable data we could get from Wotan would be a sequence of high resolution images of the whole planet covering a full rotation, and we've brought a set of transfer lenses for the telescope, like eyepieces for the multispectral camera, which are almost as good as a zoom lens, just for that image sequence, which I collect as we approach.
We don't like the radiation levels in Wotan's van Allen belts, but Wotan's magnetic field is such that we can sneak up the magnetic axis into a low orbit, similar to what we did on Njord but much steeper (and this time from the south). It's a nerve-wracking maneuver involving several changes of orientation, which are difficult for our ship, during which the word ``splat'' runs through my mind as the cloud bands and south pole of Wotan expand in the external view like a dart board from the dart's point of view. But we keep our fears to ourselves, and Tiger follows the preplanned trajectory and gets us into orbit with a minimum radiation dose and minimum disturbance to the Chang plants.
Tiger: Whew! That was scary; I'm a little shaky, and I think I should take a short nap. Simba, would you wake me in half an hour? And could you get the orbiter out to Thor?
Simba: I'm shaky too! Don't worry, I can handle the orbiter; I know your part was tough. And by the time you wake up we'll have the images coming in.
Willie: I can't say I'm an expert in planetary plasma physics, but I don't think anyone's ever gotten a complete record down the magnetic axis like that. The people back on Earth will be salivating over our data.
Me: Check out the cloud!
We're over something like Jupiter's Great Red Spot, but this one has radical waves around the perimeter and it seems to be spewing off little hurricanes in all directions. You can't see the motion in real time, but a time-lapse sequence should be spectacular.
Researching Wotan is a lot different from doing Njord; it's all weather and plasma and decametric radiation and stuff like that: mostly Willie's department. However I'm not sitting idle; I have my own planet, Thor. We're going to get a complete photomap of it like we did for Njord, using the orbiter, and its partner if we get it built in time. If necessary we'll leave for Freyja and let the orbiters finish the map without close supervision. On the way to Wotan we uploaded a new program so we could ask the orbiter for several hundred frames ahead of time, rather than telling it where to point, downloading the picture, then telling it the next one. If we're at Freyja we'll have several hundred frames traveling to us at the speed of light, and a list of the next several hundred saved in the orbiter, and another batch on its way through the aether. Growing up confined to a planet we're used to lightspeed being essentially instantaneous, but at interplanetary distances that model starts breaking down, and between the stars light resembles a snail. Tiger laughs at this analogy: when computers use the chips she designs, the width of a laptop machine is like the distance from Wotan to Freyja is for us.
Me: Planets are a lot more interesting when there's a surface to look at, aren't they?
Tiger: That's right; I have a lot more empathy for Thor than for Wotan. This frame looks like the boundary between a highland and a plate surface. There aren't many craters.
Me: That's right. On Luna every square meter would be either in a crater or buried by its debris. The low-res view shows something interesting coming up, possibly a mid-ocean ridge. Just a sec... This frame. See the central rift valley, and switch to far infrared, see the rift is much hotter. Definitely it's a mid-ocean ridge, and that means the plate surface has been exposed to cratering for no more than fifty or a hundred million years. That's why there are so few craters. So Njord, Thor and Earth have a similar tectonic style, whereas Venus has a thick rigid crust. I don't have the experience to guess why.
Tiger: Check the altimeter; we're going over a hole.
Me: Oh, look at the trench; it's a chasm! That sucker is ten thousand meters deep and you can see all the way to the bottom. There's no sediment to fill it up. And here comes the continent edge; look at the funny volcanos! They're just globs of lava piled up. On Earth the subducted oceanic crust melts into that kind of sticky lava but it's full of seawater and carbon dioxide from the shells of little sea creatures that make up the sediment. So it goes pop, or boom, when it comes up and it makes ash volcanos like Fujiyama. Or Mt. St. Helens. Njord has ash volcanos too because its subducted plates went down when there still was an ocean.
Tiger: As we go east over these mountains the surface seems to get more rounded. And is that a transform fault?
Me: Looks like it, maybe like the San Andreas fault on Earth, cutting a piece off the continent. I'll bet these mountains, oops, it drops off here into plate surface. I'll bet the eastern mountains are the oldest, and crater debris, regolith, has fallen on them thicker than on the new volcanos.
It looks like Thor never had any water on its surface. Occasionally from our own ship we see the star being eclipsed by Thor, and we're then able to use our spectrometer to get infrared absorption spectra of its atmosphere. Its atmosphere's density is about 4.5% of Earth's, a third nitrogen and the balance transparent to infrared, probably argon. There's a small trace of carbon dioxide but the regolith covering the surface would react with it. Ultraviolet light would have broken up any water or ammonia. Likely something large hit Thor late in the process of assembly and blew away its volatiles.
During the next eleven days my main duty is to collect, organize and analyze the incoming mapping data for Thor, while Willie concentrates on plasma and meteorological observations of Wotan, which is rich in those areas. Tiger is working within materials constraints to prepare subsystems for the lander, such as cameras, an alpha, proton, X-ray fluorescence spectrometer to identify rocks, a grabber arm for returning solid samples, and an atmospheric and liquid bottle sampler. Simba's main responsibility is our food supply, for the little Chang bushes have put out a few inconspicuous flowers per eighty gram bush and are just a week or two away from finishing their first seeds. We aren't going to harvest them by hand; Chang bushes come with a unique harvesting accessory, which Simba has thawed out and is hand feeding and nursing through radiation sickness: acacia ants. The oldest bushes have developed their formicatories, and Simba is moving ants in as the new apartments open up.
Finally the miner delivers its cargo to us. We transfer the comet dust to our own bag, then send the miner back out to scoop up some more. Whatever time Willie has left after his observations he spends supervising the smelter and the rolling mill, but the rest of us try to squeeze enough time to keep it operating continuously, flattening out metal strips and bending them into channels to make the chassis of the lander and the second orbiter. Tiger assembles components as they become ready. Finally the big day arrives.
Tiger: Did everyone brush her fangs after breakfast? I don't want to have to do any dentistry on this mission. OK, we're getting round the corner, I think: by shimming the piezo discs I got all five sample bottles to hold vacuum overnight, and... there they go; the shims are thin enough this time that the controller can get them to open. I'm going to put them on the orbiter the way they are. And Simba, how much sheet metal work did you finish last night?
Simba: I did the bottom cover and the last side cover. They're with the other three covers.
Tiger: Then that's everything. Yesterday I did a complete system check and all the units worked except the sample bottles. I want to launch this sucker, and all I have to do is mount the sample bottles and put the covers on. Simba, how are the ants coming? Can you help me with the launch in one hour?
Simba: I have a pupa emerging, but it won't really need attention until after lunch. No problem.
Tiger: Radiation damage?
Simba: It looks reasonably healthy so far. Not like the last one.
I have an urge to volunteer to help Tiger with the sample bottles, but I hold back. Tiger has made it clear, particularly to Simba, that initiative and a sweet disposition (in contrast to her own) are valued, but if any of us need help we're to speak up, and if we don't speak up, unsolicited offers of help had better be prefixed with a truthful report of the form, ``hey Tiger, I don't have anything to do right now.'' I do have images to go over, quite a lot of them, and that's what I stick with.
In fact, on Thor I'm starting to see an interesting pattern of faults through the continental areas. On Earth most earthquake faults involve up-down motion. Sideways faults aren't rare, but the San Andreas fault system in California and the Altyn Tagh in Tibet are just about unique in their length and the amount of slip that's occurred on them. Whereas on Thor the plate surface seems to spread at wildly erratic rates from one section to the next of the mid-ocean ridge, and the resulting active fracture zones extend throughout the basalt plates, that would be ocean bottom on Earth, and slice through the continents. Not every ridge offset generates a throughgoing transform fault, but some of them do. Maybe on Earth the fracture zones get welded together somehow, so the plates always move as units, but here they move as individual strips within the overall plate organization.
And three of the images taken overnight extend three continental transform faults that I've been tracing, and a fourth shows a transform fault going right into a subduction zone, and I believe that's the extension of one of the three continental faults.
And now it's time for the launch; I switch to an external view. Tiger isn't a slavedriver. I always had a little trouble, inside me, with bosses, resenting the way they push a person around, but Tiger isn't a boss in the usual sense. We have a very difficult and demanding job to do here and she expects it to get done, but she also wants to be happy to wake up each morning in what she calls this overpowered phone booth, and she expects us to feel the same way. This means, right now, that I don't need permission or junk like that to take a look at an important event in the mission.
The aft panel of our cabin gives access to our tiny airlock. Tiger and Simba lift the panel and stuff the lander in. All of our spacecraft have to fit into that rectangular space, into which I myself fit with my legs drawn up to my chest whenever I want to leave or enter the ship. One of our luxuries is a Roots blower in series with a turbomolecular pump, which together can clear the airlock in five minutes. Heavy, but worth it for morale, said Tiger. A pusher chip on the exterior door makes it open inward. With her joystick Tiger eases the lander outside, and I can see it on the exterior view. She turns it base forward and engages the pushers, raising the force over a period of thirty seconds or so up to two G, twenty meters per second squared. The small lander is out of sight before that level is reached.
Tiger: Well, that wasn't particularly dramatic, was it? The pushers are behaving themselves and the control system is keeping the lander stable. So let's go get some samples of Wotan. Unless Claude left an article out of our newsfeed, this will be the first sample ever returned from a gas giant planet. It's an obvious experiment but I haven't seen anything saying they did it on Jupiter, as far as we've read until now. Remember how much trouble we had with the pushers on the Hawking Telescope rescue? I can accelerate the lander at two G, and a lot less power is wasted because the chips are better, and all the heat goes back to Earth. So now we wait for half an hour for the lander to slow to zero velocity, and then we'll make the descent.
Willie: Cross your fingers, that nothing breaks.
Tiger: Right, we've put a lot of ourselves into that lander. I don't mean just our sweat, and cutting my finger on the lower frame member, though our time is valuable. There's space on the chassis for six sample bottles, and do you know why there are only five?
Willie: Because there was only enough zirconium to make five piezo valves.
Tiger: Right, because we ran out of lousy zirconium. I'm going to feel a whole lot happier when we have our own sundipper operational, but you know what's limiting on that? Gold! The gold we brought with us is enough to make contacts on one sundipper chip set and its partners. We got a few micrograms out of our comet dust: far from enough for another, and barely enough for even one pusher chip. What's going to be next? The copper supply is a joke. We have barely enough vanadium for the Chang bushes; not enough to use our titanium because it needs eighteen percent vanadium as an alloying component. Plus tin, which we also don't have. The molybdenum in the comet dust is useless; our nutrition supplements have more than it does. I would feel a whole lot better with a gram of gold, two grams of indium, about a hundred grams of molybdenum, fifty grams of tungsten; I don't have to go through the list of what we aren't getting from the dust. What's the matter here; did they miss their supernova? We have to be thankful for what we have, at Earth. I suggest that we make an orbiter that's dedicated to finding comets, specifically to finding a burnt-out comet head, so we don't have to go through so much volatiles to get the solids. Or preferably several comet heads, and we'll pick the one that has the highest trace metal concentration. Then we put a smelter on it, automated, and mine hell out of it.
Willie: That's a lot of work.
Tiger: When we need the metals it's too late to start obtaining them.
Willie: I didn't say we shouldn't do it. But we'll have to be flexible about working on mining versus doing science and building other spacecraft, which sooner or later we'll probably want. We should keep the existing miner working on our comet, in any case. Also, the electrolytic cells in the smelter don't use critical materials, but they're intricate and high precision pottery, basically, and it would take a lot of work to learn how to duplicate them. We should plan on using the existing smelter for quite some time.
Tiger: Agreed: use the existing smelter until it breaks. Get the picture?
Willie: Got. OK, I'll make a plan for learning high-tech pottery. Now there's a second point: dead comets are black. We should be looking for far infrared radiators. You'll have to let me do some formulas, but I think we're talking millimeter waves here, or hundreds of microns, and not a lot of power. We're probably going to have to make an aluminum mirror and a real fancy detector, which one or the other of us will have to learn to build.
Tiger: That's a problem, isn't it? I don't actually use millimeter waves in my chips, but I've picked up the principles. You figure out the mirror, OK? And I'll take responsibility for the detector. I'm thinking of photoconductive sensor pixels on silicon, doped so as to create low-lying impurity states that the far infrared can excite. But I'm going to have to bone up on that stuff; it's going to take a big investment of my time and of the chip maker's time. It's a real hard call: do we just hope that everything will work out, or do we get aggressive about dealing with a threat that might not materialize? Simba and Wilma, got any thoughts?
Me: I do have one. We should be looking for ore deposits on Njord. The plate surfaces are probably littered with sulfide ore complexes. On Earth we don't have the technology to go underwater and dig them up, but the great copper ore bodies are in the remains of oceanic crust that got accidentally stuck into continental areas. One or two shovelfuls would give us more copper than everything we've gotten so far from the comet.
Tiger: That's a good point. But we also need materials that aren't chalcophiles. Certainly if we find an ore body we should take advantage of it, but I suspect that only copper, zinc and lead would be useful targets for deliberate prospecting, given the time we have available.
Me: That's probably true, but we might get a lucky surprise when we start poking around on the surface.
Tiger: Cross your fingers. Look, the lander has nearly stopped. It's time to go down into Wotan.
Simba: I wonder what's down there. We've always speculated about living creatures floating and flying in the atmosphere of a gas giant.
Tiger: If they're there we should see infrared and optical bands from chlorophyll, and we don't.
Simba: True, but let's keep our eyes open.
We get a complete profile of temperature, pressure, sound speed and infrared absorbance, on the way down to a pressure of 1.5e5 pascals, a little higher than Earth's surface pressure. The camera shows stunning galleries of colored clouds as far as you can see. A distant thunderstorm looks monstrous, and we can match up lightning flashes and decametric radiation that we pick up on our starship, but the landing site is beyond our horizon and we can't look for the storm from up here. The sample bottles are filled at various levels that the spectra suggest are characteristic of particular chemical species, such as water or ammonia clouds. When we get the lander back up, Simba and I go outside and feed a small amount of each sample into the mass spectrometer. Willie has the spectra by the time we get ourselves and the lander back into the ship, and we do additional chemical analysis of the samples. While it's exciting to be the first people to analyze samples from the ``surface'' of a gas giant, we were pretty sure what we'd find, and the mass spectra and chemical analysis weren't startlingly surprising. When we get back to Njord, we already know that we'll find surprises and mystery in the air.
Each round trip takes about two hours, and we make ten descents into different weather contexts over two days, overlapping chemical analysis with flying. We're able to correlate the water and ammonia content of the samples with the types of clouds they were collected in. On the last descent we take a risk: we send the lander well ahead of us before it starts to brake, so we'll pass over the point of entry. Then we deliberately head for a thunderstorm as seen by the lander, and we're able to watch it from up here, lightning and all. Winds are like a tornado, up to Mach 0.4. There's no microphone in the lander but Tiger interprets some jerky motion as hail impacts, and she decides to grab a sample and get out of there. And a good thing too: when we get the lander back the covers are dented and battered, and a big hailstone hit awfully close to the camera port.
We could have lost the lander, and that would have been very annoying, for it would have taken four or five months to mine enough zirconium to replace the piezo valves, plus the metals for the chassis, plus the pusher and computer chips, camera, etc. etc. But our mission would not have been terminated. In this mission Tiger's main job is risk management: getting the most science possible despite unplanned happenings and circumstances, up to and including our premature death. Seen in that perspective, we got a lot of valuable information about meteorological processes on Wotan by taking a moderate risk. I think Tiger is doing a good job of risk management, and we're doing a good job by keeping our fears in perspective. Various categories of fears. Usually. Willie and Tiger are taking the covers off the lander, to check for damage inside.
Me: Simba, that damage is scary. Could you just hold me a minute?
Tiger: Go to your mate, Willie; I can handle this. So far it's only external dents.
Me: I'm sorry, people, to get so emotional.
Tiger: I take breaks too, you remember, when I'm jittery. We all should. This place is scary and nobody should be shy about feeling it. Actually, Simba, if Willie can take care of Wilma I'd appreciate a hug myself.
I suspect that Willie appreciates the chance for comforting as much as I do. Over Willie's shoulder I trace with my eyes the vines that Simba painted on our wall. There's a peaceful forest somewhere out there beyond the hard vacuum and radiation and planets that don't care what they do to our lander and to us. It's calming to think about that. It only takes a minute or two for us all to get our emotional selves steady.
Tiger: OK, Simba, enough. Help me with the panels, OK? It looks like the covers kept the hailstones off the fragile parts of the lander. I think that's the last episode of our Wotan research. Are you people ready for a trip to Thor, or should we start tomorrow?
I untangle from Willie and give him a loving pat on the butt.
Me: I'm up to it. I was just upset by the beating the lander took. Willie? Simba?
Willie: I'm in good shape. Let's do it.
Simba: Let's get started now; I don't want to sit around for the rest of the afternoon and evening doing nothing. I want to get back to Njord.
Isn't it nice to have gobs of free (or already paid for) power? Even so, we're limited to one third G by the agricultural pods, so reorienting our orbit to pass over the poles of Wotan takes about four hours, half an orbit, during which we eat an early dinner. After that we have a snaky path to follow in which we build up our speed starting about thirty degrees south, but holding ourselves close to Wotan until we're pretty far north, to stay under the strongest parts of the radiation belts. Again the orientation changes are tricky with all the pods strung out in back of the ship, but Tiger has optimized the trajectory and she accomplishes what was planned, as Willie records another plasma profile on the north polar axis and I swap lenses in the multispectral camera and snap an inverse of the sequence of pictures we got on the way in. The acceleration is gentle and during the journey I'm able to take the lander to the aft end of the cabin and assemble the grabber arm and rock pockets onto it, working twenty minutes at a time between camera exposures. I'm surprised how much I've grown accustomed to zero G; my strength seems undiminished due to our exercises, but I keep letting go of tools or the arm and assuming they'll stay where I left them. Simba takes over for some more zaggy maneuvering to toss us around the outer edge of Wotan's van Allen belt, but Tiger returns to the helm, or joystick, to drop us into orbit around Thor, and it's well past midnight when that's done. Tiger suggests that we sleep late tomorrow morning.
We awake at nine, and we take a leisurely hour to stretch, exercise, wash up, and eat our ration bars. We've found that with the frozen Chang seeds our best meal plan is two ration bars for breakfast, one bar for lunch, dinner and evening snack, and mashed, stewed, toasted or whatever style of Chang nonsprouts as the main dish for dinner, plus a vegetable or fruit if one has ripened during the previous day. I'd like to eat a little more, and more variety, which will come as the vegetable vines and bushes grow bigger, but we're not suffering. Willie and I, as well as Wolf and Wooly, were always in excellent physical shape, though lacking the bulging muscles and other components which get you on a magazine cover, but now we're losing that well-fed appearance and I think we look better for it.
Tiger: Bellies all full, people? Brush your fangs, then let's get to work. Wilma, shall I fly the lander or do you want to?
Me: I don't want to break it this early in the mission. You land it and I'll move it around on the ground. Look at the image for 21.1 east 5.8 south and overlay with my map; here it is. The red X's, the one marked `1' is where we should go first.
Tiger: And conveniently it's about a third of an orbit ahead of us. Let's get the lander out the door, and it can go right down.
Simba and I wrestle the lander back into the airlock and start up the vacuum pump. Tiger wrote a program to optimize descents like this. As soon as the door opens she eases the lander out and starts it decelerating at two G. The descent takes about ten minutes.
Tiger: This is the mid-ocean ridge system. How rough is the ground going to be?
Me: I'm not sure, but on Earth the ridge axis tends to be rough. We may have to hover. It looks like we're about to find out.
Tiger: Here's a fairly flat spot. In fact the whole area looks like overlapping basalt flows, like on Hawaii or Iceland. Here's your X, right... here. OK, it's all yours. Underwater, lava like this would cool immediately into pillows, but when it comes out in atmosphere it stays liquid and spreads.
Me: I think you're right. OK, let's start the APX spectrum.
I spend the next four hours exploring along the spreading center between the two plates. There's a big crack at the exact boundary and I can tip the camera downward and see red-hot magma at the bottom; but no way am I going to risk our lander to try for a sample. But the edge of the crack is flaky and I'm able to grab off a small flat rock sample: the only loose piece in the whole area. Beside the gentle outflow style of the magma, another big difference from Earth is the lack of hydrothermal circulation. The distance I went along the ridge axis, on Earth I would have seen several vent complexes where hot seawater rises after circulating through cracks in the hot rock, thick with sulfide minerals and associated life. Here the metals, which we would so much like to obtain, just stay in the magma where they were extruded.
I make a small suborbital hop to the next location, a mid-plate hotspot ridge. As with Hawaii and many linear island features on Earth, the hotspot has poured out magma for many millions of years as the plate moved over it, making a ridge with bumps which on Earth would be individual islands. I put about four hours into a sequence of APX scans at various places along the ridgeline to assess the changing composition of the lava. The APX machine has a bit of radioactive americium-241 that we brought from Earth. The alpha particles backscatter off the light elements like oxygen; midrange elements like silicon react with the alphas to produce protons, which the machine can detect; and heavy elements give characteristic X-ray fluorescence. It's a highly versatile way to assess the composition of rocks. This kind of study would be hard to do on Earth, because everything is drowned in the ocean, though with the advent of pusher chips ocean exploration should be somewhat easier now. By the time I get to the currently erupting end of the ridge and pick up a few samples, it's time for dinner and time to call it a day. I fly the lander home, but I let Tiger do the final approach and gently slide it into the airlock.
The next day's exploration is along one of the transcontinental transform faults. There's essentially no erosion on Thor, and the fault slices through the rock and exposes it in cliffs. I hope to take a spectrum about every ten kilometers for about 600 kilometers: a very full day of observation. I'm about halfway through when I notice something odd.
Me: Tiger, would you look at the spectrum for the previous site? Since we're short of zirconium, that area has enough that it might be useful to go back and scoop up a big sample.
Tiger: How much zirconium?
Me: About a tenth of a percent.
Tiger: So we'd need... Let's finish this transect, and then just for laughs, come back tomorrow and search that area in detail. Maybe we'll find something else interesting. We'll make several trips and bring up about twenty kilos of rock, and refine it into twenty grams of zirconium, and whatever else it has that's useful. That's going to be really helpful, having enough zirconium for extra piezoelectric motors and things. And we can have the sixth sample bottle on the lander too.
Me: People say gravity sucks; what's useful about a planet? What's useful is chemical differentiation: by mining that spot for a few hours we can get as much zirconium as we did in three months of mining comet dust.
Tiger: That's a real good point. Maybe we're being stupid about the mining business. I was real gung ho about the comet miner when we should have been concentrating on the planets, right?
Me: Well, there are elements that sink to the core and stay there, like cobalt and nickel. Comet dust and planetary impact sites are where you find those.
Tiger: And where's the most concentrated source of comet dust? Not on the comets. Let's think this through: comets hit the planets and splatter, a certain amount per unit area per year. The areas that survive subduction the longest have the most dust. That means the eastern side of this continent.
Me: And I think Loki is too small for much tectonic activity. I'll bet we find even more dust on Loki. But the regolith where we're exploring has bits and pieces of Thor's crust, which is differentiated. And the reason I'm looking on this fault line is to find what might have fallen off the cliffs, as a clue to the planet's history. But equally it could be our gold mine. Not literally, but we've found one useful mineral and we might find more.
Tiger: Right. I want to discuss it with Willie and Simba...
Willie: Discuss what?
Tiger: Mining policy; transferring our attention to planetary surfaces. But let's talk later when we're not in the middle of other work, OK?
Me: I'd like to continue the idea of an orbiter that would search for comets. That's going to be very valuable scientifically.
Tiger: Agreed. I wasn't thinking of... Well, there's a lot to think through, and that's one item on the list. And now isn't the time for deep thoughts.
Me: Right, the spectrum is done at this site. I'll move the ship and you see what neat stuff we might have been sitting on.
Neat it is, when Tiger analyzes the spectrum: there must have been a tiny fragment of scheelite, calcium tungstate, under the APX head, and we're definitely going to go back there too and look for its big brother. And about 100 kilometers down the fault, at the base of a high cliff, we strike gold. From its next stop we bring the lander back to grab a rock sample, and at the end of the day when we bring it up to the ship we find that we got a piece of granite laced between the grains with tiny flakes of gold, about fifty micrograms per kilo. That's not a lot, but what's in our sample is actually enough for the interconnects on one small pusher chip.
A prospecting mission the next day turns up a good deposit of zirconium silicate, common name zircon or jacinth, and a kilo of that gives us enough zirconium for all the piezo valve crystals we'll ever need, and we have the coordinates so we can go back for more if Tiger has estimated too conservatively. The scheelite also can be localized and we score a quarter kilo of tungsten after smelting. We search the talus at the cliff foot in detail, and we chance upon a narrow zone of euxenite presumably fallen from an ore body above. That's Greek for ``really weird mineral'', and it yields a weird collection including niobium, tantalum, yttrium, cerium, thorium and uranium: five to twenty grams of each in the load we bring up, plus a lot of irrelevant dirt. None of those are immediately useful but we consider the time well spent on filling the sample pockets, bringing the lander up, and running the ore through the smelter, just in case we have a future unexpected need. Well, Tiger has three tantalum pins in her skull that held it together while she recovered from her accident, but I trust we won't be using tantalum in that way on this mission. Vanadium would be extremely welcome, but there's not a trace of it.
The gold mine is quite a success. During the afternoon we sniff through the talus and we're able to actually see on camera chunks of granite with sparkles in them. Loading the rock pockets with about ten kilos of the best pieces, we haul up eight milligrams of gold, taking an hour and a half to do it. With practice we get the round trip time down to an hour, and we manage eight trips before our bedtime. Thor rotates, and revolves around Wotan, in 38.5 hours, so the mine site will be dark when we wake, but the light is plenty as long as we want to work today.
Tiger: So how much did we get finally? Are we rich beyond the dreams of avarice?
Willie: 72 milligrams total. You can see it, but it's not very much. Does anyone know the current price of gold, or what it was when we left?
Simba: About 350 dollars per troy ounce or a penny per milligram. We earned 72 cents for our work this afternoon and evening.
Tiger: It's worth it. We've used about eighty milligrams, out of our supply of one gram, on chips so far for our orbiter and lander and barbell and so on. Before, it was taking us outrageously long to get gold from comet dust. Now, if we decide to build something with a lot of chips, like a sundipper, we can spend a reasonable time at this mine and get what we need. About two weeks per sundipper, I calculate, if we can duplicate our performance. We don't need to dig up a lot of gold yet; I think we ought to leave tomorrow; but when we do need it we can get it. Being sure of that was worth the time we spent today.
Willie: You were talking yesterday about focusing our mining effort on Thor and maybe Loki and Njord, rather than mining the comets directly. I think we've kind of proved that's a good idea.
Me: Don't forget cobalt and other siderophiles; but likely we'll find a lot of those on the surface of Loki. I have a suggestion. We should build another lander that's specialized for prospecting. We can't afford human time to search in detail for minerals, but we can point out a likely area to the prospecting machine, like this fault line, and set it loose there while we do our proper work. What do you think?
Tiger: I think that's an excellent idea, and the prospector should probably come after the second orbiter and before the sundipper. Now let's have a bedtime snack, brush our fangs, and get some sleep. I'll need to wake up half an hour early, so we'll be in the right phase of our orbit when we want to warp out of here. The rest of you can just get up at the regular time. Next stop: Freyja.
It takes us six days to go from Thor to Freyja. We leave the orbiter circling Thor to finish the map there. On the way Tiger finishes the second orbiter and we send it off to start mapping Loki. We have a big milestone, and turn it into a spring celebration: our first harvest from the Chang bushes. Simba harvests about half a kilo of seeds, and over the next week or two the plants will work up to producing three hundred grams per day. That's not much, but anything is welcome. We have a hand-powered grain mill, and Simba turns the half kilo into flour, six flavors mixed together, and makes us a squash pie, putting in two zucchinis and a crookneck squash. I'm thankful that the Chang bushes are working out. We plan to put the crop into storage but to eat 150 grams per day of the oldest seeds, or half the input as we get more production, until we run out of ration bars and frozen failed sprouts. Then we'll have to build up reserves more slowly, but eventually we want a hundred kilos in case of another disaster.
Travel between planets gives us a good opportunity to read news. And here's a nice series of notes from Wooly: she's out of college, has a good job, and has a steady boyfriend. He's Jamaican, and he has a beautiful accent: she sent along some voice files. I wonder if he'll do good by my little girl, though. You never know, those Jamaicans. If I were back there I'd be in heavy mother-daughter mode, but I'm just going to have to put that out of my mind, and hope to see a nice family and not a divorce when I thaw on the other side. She wanted to be on her own, and she got her wish. Will I get mine?
There's' a lot of stuff here: the Eridanus Corporation is receiving rivers of money, so we don't have to worry about being stranded out here. Our trust account is growing nicely under Claude's care. Oh, there's a disappointment: nice President Faraldo didn't get re-elected; Martin won it. Too much association with lions? No, the summary says candidates from the other party brought it up occasionally but too many people like lions for them to use the issue effectively. The problem was that Faraldo was blamed for the Social Security mess. Unfairly, Simba says. Anyway, my less favorite party is now in the White House. But the Senate also changed hands, so again the legislative process is going to be deadlocked. We Americans have such a bizarre system of government. But do you suppose we'd like to do it Chinese style?
And the Chinese have stopped putting out progress reports on their starship, and Claude says it's an open secret that they've pulled their sundippers into a parking orbit. I don't like to think about that. It could happen to us too, on our way back.
On arrival at Freyja we find that it's a beautiful cream color, but it's something of a disappointment in the area of science. It's a gas giant like Wotan, but since it's smaller and gets less sunlight (epsilon-light?) all the activities are less energetic and complex. While Wotan had galleries of thunderclouds Freyja has light fluffy cloud layers, for example, and no persistent vortices. We were supposed to spend twenty days on it but we've collected about as much data as we're going to want after ten days. A bright spot for me and Willie is some pictures that Wooly sent from her vacation; it looks like she and Wallace are getting serious. I hope he's a good mate for her, like Willie has been for me.
The first orbiter having finished up Thor's map, we have it meet us at Loki. Our journey there takes four days. Loki is interesting as a contrast to the other planets. It's bigger than Luna but smaller than Mars, and it has a modest atmosphere of argon and nitrogen, carbon dioxide and ammonia being frozen on the surface and methane having been photolysed into smog. Loki shows the scars of early tectonic differentiation and meteor bombardment, much like Luna, but that didn't last long, and Loki's crust has been quiescent for aeons. The surface is covered with craters and dust, and it's a trove of iron and its friends: cobalt, nickel, platinum, and a variety of chemically related elements. And at last, vanadium and phosphorus are available in low concentrations. With the lander we explore the surface for scientific interest, but we also fill the rock pockets with regolith on every ascent, and we get enough phosphorus to fertilize the Chang plants properly, and enough vanadium and tin to make a few kilos of beta-titanium alloy.
And now we're returning to Njord, at the end of a five day journey, and I can relinquish center stage to Simba, who will take the lead in the search for extraterrestrial life.